Canon EF-S 55-250mm f/4-5.6 IS - Retest @ 15mp / Review - Analysis
Lens Reviews - Canon EOS (APS-C)
Thursday, 15 January 2009 09:00

Distortion

The EF-S 55-250mm produces a moderate degree of barrel distortion at 55mm (~1.1%) and slight pincushion distortion beyond (~0.7%).

Move the mouse cursor over the focal length text marks below to observe the respective distortion
55mm 135mm 200mm 250mm

The chart above has a real-world size of about 120x80cm. Please note, that these charts have been copied from the first review - these figures can't really be any different only because of a new testing DSLR.

Vignetting

Being a dedicated APS-C lens the Canon EF-S 55-250mm f/4.5-5.6 IS produces comparatively high vignetting close to 1EV at "large" aperture settings. This may be disturbing at times. Beyond the max. aperture it isn't really a problem anymore.

MTF (resolution)

The lens produced pretty decent resolution figures in the MTF lab. The resolution characteristic is generally very good across the image frame. Unsurprisingly the lens performs best at 55mm resulting in very good to excellent figures. There's deterioration towards longer focal lengths with 200mm being the weakest spot but it's not overly pronounced - surely thanks to the effect of the large UD element in the front lens group. Subjectively the contrast level suffers somewhat at longer focal lengths though (not visible in the graphs below).

Below is a simplified summary of the formal findings. The chart shows line widths per picture height (LW/PH) which can be taken as a measure for sharpness. If you want to know more about the MTF50 figures you may check out the corresponding Imatest Explanations

Chromatic Aberrations (CAs)

The level of lateral chromatic aberrations (color shadows at harsh contrast transition) is very low and usually not field relevant at around or less than ~1px on the average at the image borders.




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